DIMM
1
2
3
6
5
4
VIN
LM3410
C
1
R
1
D
1
LEDs
L
1
R
2
C
2
C
3
R
5
C
4
R
4
D
2
R
3
D
3
J
1
1 Introduction
This evaluation board showcases the LM3410X as a boost LED driver. It is designed to drive four, onboard LEDs (V
input voltage of 3.3 V-5.5 V. The switching frequency of the LM3410X converter is 1.6MHz allowing the
use of small surface mount inductors and chip capacitors. This evaluation board also features the PWM
capability of the LM3410 by enabling the user to apply a periodic pulse signal to the DIM terminal of
varying duty cycle.
This is a 2-layer board using the bottom layer as a ground plane. A schematic and layout are shown below
along with measured performance characteristics. A bill of materials is also provided that describes the
parts used on this evaluation board. The above restrictions for the input voltage are valid only for the
evaluation board as shipped with the evaluation board schematic shown in Figure 1.
Operating Conditions:
• VIN= 3.3 V to 5.5 V
• V
• I
≊ VFx 4 + VFB≊ 2.8 V x 4 + 0.190 V ≊ 11.4 V
OUT
≊ 190 mA
LED
User's Guide
SNVA410A–April 2010–Revised May 2013
AN-1996 LM3410X 190mA, LED Driver 6-Pin LLP
Evaluation Board
= 11.4 V) in series at an average LED current (I
OUT
) of 190mA. The circuit can accept an
LED
Figure 1. Schematic
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SNVA410A–April 2010–Revised May 2013 AN-1996 LM3410X 190mA, LED Driver 6-Pin LLP Evaluation Board
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Copyright © 2010–2013, Texas Instruments Incorporated
1
Setting the LED Current
Pin Name Function
1 PGND Power ground pin. Place PGND and output capacitor GND close together.
2 V
3 DIM
4 FB Feedback pin. Connect FB to external resistor divider to set output voltage.
5 AGND Signal ground pin. Place the bottom resistor of the feedback network as close as possible to this pin & pin 4.
6 SW Output switch. Connect to the inductor, output diode.
DAP GND
IN
Part ID Part Value Manufacturer Part Number
U1 2.8A ISWLED Driver TI LM3410X
C1, Input Cap 10µF, 6.3 V, X5R TDK C2012X5R0J106M
C2, Output Cap 2.2µF, 25 V, X7R TDK C3225X7R1E225K
C3, Input Cap Placeholder (not stuffed) - -
C4, Output Cap 4.7µF, 25 V, X7R TDK C3225X7R1E475K
D1, Catch Diode 0.4 VfSchottky, 500mA ON Semiconductor MBR0530T1G
D2 15 V Zener Diode Central Semiconductor CMHZ4702
D3 0.4 VfSchottky, 500mA ON Semiconductor MBR0530T1G
L1 3.3µH, 5.4A Coilcraft DO3316P-332
R1 1Ω, 1% Vishay CRCW12061R00FNEA
R2 Placeholder (not stuffed) - R3 100Ω, 1% Vishay CRCW0603100RFKEA
R4 Placeholder (not stuffed) - R5 6.8kΩ, 1% Vishay CRCW08056K80FKEA
J1 Jumper Samtec TSW-102-07-T-S
SH-J1 Jumper shunt Tyco Electronics 2-382811-1
LEDs 700mA, Vf≊ 3.4 V Cree XPEWHT-L1-0000-008E5
www.ti.com
Table 1. Pin Descriptions
Supply voltage for power stage, and input supply voltage.
Dimming & shutdown control input. Logic high enables operation. Duty Cycle from 0 to 100%. Do not allow
this pin to float or be greater than VIN+ 0.3 V.
Signal & Power ground. Connect to pin 1 and pin 5 on top layer. Place 4-6 vias from DAP to bottom layer
GND plane.
Table 2. Bill of Materials
2 Setting the LED Current
The default forward current I
setting resistors R1 and R4 can be changed according to the following equation:
I
= (VFB)/(R1 || R4)
LED
The feedback voltage VFBis regulated at 0.190 V typically. The resistors R1 and R4 should be rated to
handle the power dissipation of the LED current.
3 PWM Dimming
The default set-up of the DIM terminal is to enable PWM dimming. If PWM dimming is not required, then
the DIM pin can be tied to VINthrough a resistor, R2, using the existing 0805 sized resistor footprint. This
enables the LM3410 whenever VINis applied and allows the set I
continuously. A recommended value for R2 is 100kΩ.
A periodic pulse signal at different frequencies and/or duty cycle can be applied to the evaluation board's
DIM terminal for PWM dimming. The voltage measured at the DIM package lead must not be higher than
0.3 V above VINfor proper operation. Diode D3 and resistor R5 have been placed in the circuit to clamp
the signal at the DIM lead to no greater than 0.3 V above VIN. Although not recommended, a PWM signal
can therefore be applied to the evaluation board DIM terminal with a peak voltage greater than VIN.
2
AN-1996 LM3410X 190mA, LED Driver 6-Pin LLP Evaluation Board SNVA410A–April 2010–Revised May 2013
delivered to the LED array is 190mA. To adjust this value, the current
LED
current to flow through the LEDs
LED
Copyright © 2010–2013, Texas Instruments Incorporated
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200
180
160
140
120
100
80
60
40
20
0
0 10 20 30 40 50 60 70 80 90 100
DUTY CYCLE (%)
I
LED
(mA)
1 kHz
500 Hz
100 Hz
DUTY CYCLE (%)
I
LED
(mA)
200
180
160
140
120
100
80
60
40
20
0
0 10 20 30 40 50 60 70 80 90 100
100 Hz
500 Hz
1 kHz
www.ti.com
4 Over-Voltage Protection
The evaluation board includes over-voltage protection (OVP) circuitry, in the combination of zener diode
D4 and resistor R3, to protect the LM3410 device in a situation where the output load is suddenly
removed from the rest of the converter (i.e. an LED goes open). A header (J1) on the board allows the
user to activate the OVP function by removing the associated jumper. The switching voltage at the SW pin
will then be clamped to approximately the zener diode voltage of 18 V. Current will then flow through D4,
R3 and sense resistor R1. This generates a voltage greater than 0.190 V at the FB pin that forces the
LM3410’s internal switching power FET to turn off, thereby, preventing an over-voltage condition at the
SW pin and damaging the LM3410.
5 Typical Performance Characteristics
Over-Voltage Protection
TA= +25°C, V
Figure 2. PWM Dimming, VIN= 3.3 V Figure 3. PWM Dimming, VIN= 5.5 V
= 11.4 V, unless otherwise specified.
OUT
SNVA410A–April 2010–Revised May 2013 AN-1996 LM3410X 190mA, LED Driver 6-Pin LLP Evaluation Board
Submit Documentation Feedback
3
Copyright © 2010–2013, Texas Instruments Incorporated
I
LED
(mA)
6.0
5.0
4.0
3.0
2.0
1.0
0.0
-1.0
-2.0
-3.0
-4.0
-5.0
-6.0
500
400
300
200
100
0
-100.000µ 100.000µ 300.000µ 500.000µ
V
DIM
100 Ps/DIV
0
2
1
3
V
DIM
(V)
I
LED
I
LED
(mA)
6.0
5.0
4.0
3.0
2.0
1.0
0.0
-1.0
-2.0
-3.0
-4.0
-5.0
-6.0
500
400
300
200
100
0
-100.000µ 60.000µ 220.000µ 380.000µ 540.000µ
V
DIM
100 Ps/DIV
0
2
1
3
V
DIM
(V)
I
LED
I
LED
(mA)
6.0
5.0
4.0
3.0
2.0
1.0
0.0
-1.0
-2.0
-3.0
-4.0
-5.0
-6.0
500
400
300
200
100
0
0 0 0 0 0
V
DIM
1 ms/DIV
0
2
1
3
V
DIM
(V)
I
LED
INPUT VOLTAGE (V)
EFFICIENCY
(%)
100
95
90
85
80
3.0 3.5 4.0 4.5 5.0 5.5
Typical Performance Characteristics
Figure 4. Efficiency vs. Input Voltage, Figure 5. 500Hz PWM Dimming,
I
= 190 mA 50% Duty Cycle, VIN= 3.3 V
LED
www.ti.com
4
Figure 6. 500Hz PWM Dimming (Rising Edge), Figure 7. 500Hz PWM Dimming (Falling Edge)
AN-1996 LM3410X 190mA, LED Driver 6-Pin LLP Evaluation Board SNVA410A–April 2010–Revised May 2013
50% Duty Cycle, VIN= 3.3 V 50% Duty Cycle, VIN= 3.3 V
Copyright © 2010–2013, Texas Instruments Incorporated
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DIMM
1
2
3
6
5
4
VIN
LM3410
C
1
R
1
D
1
LEDs
L
1
R
2
C
2
C
3
R
5
C
4
R
4
D
2
R
3
D
3
J
1
VPWR
C
5
www.ti.com
Two Power Supply Design with 12 V > V
PWR
> 5.5 V
6 Two Power Supply Design with 12 V > V
The evaluation board can be modified to allow the user to derive the power from an input supply that is
larger than 5.5 V. In Figure 8, two separate supplies are needed. VINmust be between 3.3 V minimum to
5.5 V maximum, but V
V
. Power-down should be in the reverse order.
PWR
can be as great as 12 V. The recommended power-up sequence is VINthen
VPWR
PWR
> 5.5 V
Figure 8. Two Power Supply Schematic
Table 3. Bill of Materials (BOM) - Two Power Supply Design
Part ID Part Value Manufacturer Part Number
U1 2.8A ISWLED Driver TI LM3410X
C1, VIN, Input Cap 10µF, 6.3 V, X5R TDK C2012X5R0J106M
C2, Output Cap 2.2µF, 25 V, X7R TDK C3225X7R1E225K
C3, Input Cap Placeholder (not stuffed) - -
C4, Output Cap 4.7µF, 25 V, X7R TDK C3225X7R1E475K
C5, V
, Input Cap 10µF, 25 V, X5R TDK C3225X5R1E106M
PWR
D1, Catch Diode 0.4 VfSchottky, 500mA ON Semiconductor MBR0530T1G
D2 15 V Zener Diode Central Semiconductor CMHZ4702
D3 0.4 VfSchottky, 500mA ON Semiconductor MBR0530T1G
L1 3.3µH, 5.4A Coilcraft DO3316P-332
R1 1Ω, 1% Vishay CRCW12061R00FNEA
R2 Placeholder (not stuffed) - R3 100Ω, 1% Vishay CRCW0603100RFKEA
R4 Placeholder (not stuffed) - R5 6.8kΩ, 1% Vishay CRCW08056K80FKEA
J1 Jumper Samtec TSW-102-07-T-S
SH-J1 Jumper shunt Tyco Electronics 2-382811-1
LEDs 700mA, Vf≊ 3 .4 V Cree XPEWHT-L1-0000-008E5
SNVA410A–April 2010–Revised May 2013 AN-1996 LM3410X 190mA, LED Driver 6-Pin LLP Evaluation Board
Submit Documentation Feedback
Copyright © 2010–2013, Texas Instruments Incorporated
5
PCB Layout
7 PCB Layout
www.ti.com
Figure 9. Top Layer
Figure 10. Bottom Layer
6
AN-1996 LM3410X 190mA, LED Driver 6-Pin LLP Evaluation Board SNVA410A–April 2010–Revised May 2013
Copyright © 2010–2013, Texas Instruments Incorporated
Submit Documentation Feedback
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